Determination of the Optimum Moisture Content for the Whole Kernel Recovery During the Cracking Process of Oil Palm Nuts

Abstract

This study aimed to investigate the effect of moisture content on palm nut cracking and kernel production using a locally fabricated palm nut cracker. Palm nuts of mixed varieties (Dura, Tenera, and Pisifera) were manually cleaned and dried at different moisture content levels ranging from 8.53% to 26.82%. The palm nut cracker is designed with four major units: the in-feed unit, cracking unit, discharge unit and the driving unit. The cracking efficiency was determined by calculating the ratio of completely cracked nuts to the total nuts fed into the hopper. Results show that the whole kernel recovery varies considerably with moisture content and cracking speed. At the lowest moisture content of 8.58%, the whole kernel recovery is generally low across all the cracking speeds. As the moisture content increases, there is a significant improvement in whole kernel recovery at all the cracking speeds. The highest whole kernel recovery was obtained at intermediate moisture contents of around 14% to 18%, and the cracking speeds of 1000 rpm to 1400 rpm. The ANOVA table shows that both the cracking speed and moisture content have a significant effect on whole kernel recovery. Optimizing these parameters could lead to higher whole kernel recovery. However, it is important to note that other factors such as the cultivar of the nut and the equipment used may also affect the whole kernel recovery.